Pro-Russian rebels discussed moving the remains of flight MH17 victims from the crash site and even thought about scattering other plane parts in the area.

UK intelligence officials have uncovered shocking evidence which claims to show the lengths separatists were planning to go to sabotage the investigation.

As reported by Sky News, this included moving the bodies of the dead from the fields in Grabavo. In a bid to confuse investigators, they also discussed placing other plane parts across the fields where the Malaysia Airlines plane was shot down.

It was also reported that the rebels thought about sending MH17's black boxes to Moscow.

The claims come as the victims of last Thursday's plane crash made their final journey.

Coffins containing the remains of passengers where met with a military guard today and loaded onto a cargo plane, ready to be repatriated from the Ukraine.

Today was declared a national day of mourning in the Netherlands where the majority of the victims came from. Their bodies will arrive in Eindhoven so that they can be identified.

However, that process could take months and the relatives of up to 100 people may have an even longer wait because their bodies may still be at the crash site.

Five refrigerated wagons containing 200 body bags reached Kharkiv yesterday while the black boxes today arrived at Farnborough Airport, Hampshire, where they will be analysed by British experts.

Tony Abbott, Australia's Prime Minister, said that based on an initial inspection of the remains in the train carriages, that it was unclear how many bodies may still be left behind in rebel-held territory.

"Based on early inspection of the trains in Kharkiv, we just don't know how many bodies we have.

"It's quite possible that many bodies are still out there in the open, in the European summer, subject to interference and subject to the ravages of heat and animals. That is the predicament in which we find ourselves."

The king and queen of the Netherlands will lead mourners as the first victims of the Malaysia Airlines MH17 disaster are repatriated from the Ukraine today.

King Willem-Alexander and Queen Maxima will be in Eindhoven with relatives of the 298 people - including 10 Britons - killed when the Boeing 777-200 was apparently shot down by Russia-backed separatists over eastern Ukraine on Thursday.

An unconfirmed number of bodies were released by the rebels yesterday and taken to the government-controlled city of Kharkiv by train.

Two military aircraft will fly some of them to Eindhoven this afternoon, where they will be met by the royals, prime minister Mark Rutte and relatives.

The Netherlands government said a minute's silence will be held before a motorcade takes them to the Korporaal van Oudheusden barracks, where the process of identifying them will begin.

Tragic: A coffin of one of the flight MH17 victims is loaded onto a plane today (Image: Reuters)

Mr Rutte warned yesterday that this may not be a quick process, saying: "This may happen rapidly, but I have to caution you that it could also take weeks or even months."

The Dutch are leading the investigation into what happened to the Amsterdam to Kuala Lumpur flight, at the request of the Ukrainian government.

A British team of police officers, led by the Metropolitan Police, will assist with victim identification in the Netherlands once bodies have arrived.

Prime Minister David Cameron announced Britain's Air Accidents Investigation Branch (AAIB) is to retrieve data from the flight recorders for "international analysis" after a request from the Dutch government.

The European Union yesterday inched towards introducing economic sanctions against Vladimir Putin's Russian "cronies" in response to the passenger jet's downing by a surface-to-air missile fired by the separatists that the Kremlin backs.

EU foreign ministers meeting in Brussels agreed "concrete proposals" to draw up a list of the Russian president's associates who would be subject to punitive measures, Foreign Secretary Philip Hammond said.

The first names will be considered at a meeting tomorrow, where ministers will also look at broader sanctions such as arms embargoes and access to capital and hi-tech goods.

Mr Cameron has openly criticised a "reluctance" on the part of some European nations to take stronger action against Moscow, saying it would be "unthinkable" in the UK to go ahead with a French deal to sell helicopter carriers to Russia.

But MPs have warned that Britain is itself continuing to export tens of millions of pounds worth of arms and other dual-use military equipment to Russia.